Donald Trump's long-awaited pivot seemed to begin in earnest Thursday night, when — for the first time in his campaign — he expressed "regret" for the litany of off-the-cuff statements that have offended almost every group of Americans.

"Sometimes, in the heat of debate and speaking on a multitude of issues, you don't choose the right words or you say the wrong thing," Trump told a crowd gathered at a rally in Charlotte, North Carolina, Thursday evening. "I have done that, and I regret it, particularly where it may have caused personal pain."

Still, it's unclear whether Trump's newfound contrition will last. Or whether it will help move the needle in a race where more than 75% of likely voters say their decisions about whom to support are final.

"It will be at least a week or two before we know for sure whether Trump has started a new chapter, and whether voters believe him," Nathan Gonzales, a non-partisan political handicapper, said on Friday.

Blanket regret: After Trump's expression of regret Thursday night, it's likely he'll be asked pointed questions — without a teleprompter — about specific things he's said "in the heat of debate" that he now regrets.

Trump has called Mexicans "rapists;" mocked a disabled reporter; insulted his former primary opponent Carly Fiorina's appearance; said he has sacrificed as much as a Gold Star family whose son was killed in the Iraq War; said Sen. John McCain, who was taken prisoner and tortured in Vietnam, is not a war hero because he got captured; and attacked a judge of Mexican heritage, saying he could not objectively preside over cases involving Trump because Trump is "building a wall" along the U.S.-Mexico border.

Over the course of the campaign, Trump has doubled down on many of those remarks, refusing to apologize and blaming "political correctness" on why people were offended by his words.

His newly appointed campaign manager, Kellyanne Conway, did not provide any more context about his apology during an appearance on Good Morning America Friday morning.

Instead, she said Trump's blanket apology should be enough to convince voters Trump is on their side.

"I certainly hope America heard him last night, because all of the people ... who say, 'Let's get Trump to pivot, let's get him to be more presidential,' that is presidential," said Conway on GMA, who refused to say whether Trump would attempt to make amends with those he's attacked personally, including Sen. John McCain and the Khan family — whose son was killed in action in Iraq.

Will it matter? But even if this expression of regret marked a turn in Trump's behavior, his past comments may have done irreparable damage to his chances.

Trump's provided Hillary Clinton's campaign with a bevy of footage to use in attack ads against him.

And if Trump's first campaign ad released Friday morning is any indicator, his vitriol toward immigrants is here to stay — despite making a plea for minority votes Thursday night in his speech.

In the ad, Trump paints a dystopian picture of Clinton's America.

"Illegal immigrants convicted of committing crimes get to stay, collecting Social Security benefits, skipping the line. Our border open. It's more of the same, but worse," the ad says.

That message is unlikely to change the minds of Hispanics and African-Americans, with whom he desperately needs to make inroads.

Even worse for Trump, polls show a majority of Americans view Trump as "racist," including more than two-thirds of millennials.

He currently trails Hillary Clinton by an average of 5.5% nationally, according to the RealClearPolitics polling average, as well as in key swing states, making his chances of victory in November slim.